1. Field of the Invention
This invention relates to a process and apparatus for applying a refractory mass to inner walls of a vessel, especially a metallurgical vessel. More especially, this invention relates to a process and apparatus for forming a refractory lining on the interior walls of a metallurgical vessel, especially a metallurgical vessel containing the brickwork of the wall being worn by slinging a refractory mass centrifugally to the walls of the vessel in a direction normal thereto. This invention is particularly concerned with the formation of a circulating mass jet normal to the direction of the walls of the vessel and to formation of a refractory living having good density characteristics thereon. The invention is also concerned with a device for carrying out the process.
2. Discussion of the Prior Art
A process of the above mentioned type is described in the German Offenlegungsschrift No. 2,363,776. For restoring the refractory lining of casting ladles, this Offenlegungsschrift proposes that a refractory mass containing up to 4% dry binding means and 4-6% water be slung onto the vertical ladle wall using the centrifugal force when the smooth (used or worn) brickwork is at a temperature of at least 120.degree. C. A centrifugal slinging machine having two lateral arms at the end of a shaft constructed in the form of a tube conduit, said lateral arms being for the discharge of the refractory mass, serves as slinger here. The shaft is arranged in the casting ladle axis of the perpendicular casting ladle in such a way that it can be raised and lowered. The mass containing binding means is continuously slung through the rotating shaft and the circulating arms towards the ladle using centrifugal force. This forms a continuous jet of mass.
While the prior known method may permit the special refractory mass to be applied to the hot wall of vessels of lesser diameter, problems arise with vessels of larger diameter and even with vessels of lesser diameter, when the temperature of the vessel is higher, e.g., 300.degree. C. and higher; then the mass can achieve a cohesive state in the supply conduit; this leads to blockages.
When using said prior art with vessels of larger diameter more serious problems arise as with ladles of greater diameter, e.g., with a capacity of 100 tons or 200 tons. The continuous jet of the mass is splintered or spread fanwise on the long passage from the slinger to impact against the vessel wall. This causes the coarser constituents of the mass to become separated from the fine constituents due to the air resistance. There is then the danger that a high proportion of the refractory mass does not adhere on the vessel wall or, in the case where a sufficient proportion adheres, the mass is not applied to the remaining brickwork in the desired density.
In another process which has proved itself in the relining of casting ladles a slinger machine slings the refractory mass in the shape of lumps substantially vertically over a short distance into the space between the casting ladle wall and a mold (see German Auslegeschrift No. 1,483,584). In this prior art, the lump sequence amounts to about 25 lumps per second, the lumps being slung out of the slinger at a speed of more than 40 m/sec. and being packed within said space one on another.
A device has also become known for a slinging technique (German Offenlegungsschrift No. 2,035,039) which mixes the refractory mass and the binder in the slinger head immediately before slinging the mixture. In this device the slinger head is attached to the front end of an arm articulated successively in different planes and is supplied with refractory slinger mass through tubes by means of an air stream. Water is sprayed by means of spray nozzles onto the refractory mass supplied in the slinger head. The slinger head is inserted into the vessel and swivelled to all sides to line the metallurgical vessel. With this device there is the danger of the refractory mass segregating in the supply tubes due to the refractory mass being pneumatically supplied. There is also the danger of the supply tubes being damaged due to the elevated temperatures which are present when vessels are lined which are still in hot state. Besides this a pneumatical supply of the refractory mass is impossible when the mass contains a slight amount of moisture or fluid binder.
It is an object of this invention to provide a process which guarantees the formation of a high density liner on the inner walls of a vessel by employing centrifugal force to dispose a refractory mass on the inner walls of a vessel, whilst the axis of the vessel is vertical and without substantial rebound of the applied refractory mass from the vessel wall. Moreover, it is a particular object of this invention to provide a process which can be peformed in vessels of large diameter such as for example, casting ladles with a capacity of over 100 tons, particularly when the vessel wall is still hot. A further object of the invention is to provide a device for carrying out the process.